This invention relates generally to dispensing containers, and more particularly to a container for storing and controlled dispensing of sterile solutions.
A normal procedure for the user of contact lenses is to periodically remove the lenses and clean them. For this purpose, a sterile saline solution is normally used. In order to avoid contamination of the solution by bacteria before use, it is important to keep the solution from coming into contact with the air during storage, or to include a preservative in the solution. The problem with the use of preservatives in the solution is that, since the lenses are not dry when inserted in the eye, some solution remains on the lenses and the preservative in the solution can irritate the eyes.
One answer to the problem has been to eliminate the preservative from the lens cleaning solution and provide a container that prevents the stored solution from coming into contact with the air. In other words, provide a container that allows fluid to leave the container but prevents air from being sucked back into the container to contaminate the unused solution. One such container is disclosed in U.S. Pat. No. 4,739,906 by LoTurco issued on Apr. 26, 1988. LoTurco discloses a plastic squeeze container having a one-way valve that permits fluid to be squeezed out of the container but the one-way valve prevents air from penetrating back from the valve into the solution to contaminate it. The Loturco container also includes a cap which presses against the valve, further preventing air from penetrating into the container via the one-way valve. But there remains a desire for a container having the advantages of the LoTurco container with reliability in a wider range of sizes, even down to a very small size.
An object of the present invention is to provide an improved storage and dispensing device which can dispense droplets or a slow stream of an appropriate solution, and which will not permit air contact with the undispensed portion of the solution or trapped dispensed solution that could be exposed to bacteria in the air. A further object of the invention is to provide an improved device which is self-closing once the solution has been dispensed.